Dilution of Potassium Permanganate stock solution?

Question

A stock solution will be provided. Calculate how much is needed to make approximately 500-mL of 0.04 M KMnO4

Answer 1

Mstock*Vstock=Mdil*Vdil =>

Vstock=(Mdil/Mstock)*Vdil = (0.04/Mstock)*500 mL

So when they give you the molarity of the stock solution you just plug it in the equation and get the volume (in mL) of stock that you need to use.

Answer 2

ok so you need .04 moles KMnO4 in 1L which means you need .02 moles in 500ml so you just need to find the weight of one mole and multiply it by .02